Subjects | 2313 | 2061 (89.1) | 150 (6.5) | 102 (4.4) | |
Fetal sex male | | 1097 (53.0) | 73 (48.7) | 50 (48.5) | 0.37 |
Gestational age at birth | 2274 | | | | |
Weeks | | 39.2±1.7 | 39.6±1.7 | 38.9±1.7 | 0.001 |
Days | | 274.7±11.6 | 277.5±11.7 | 272.0±11.8 | 0.001 |
Placenta weight g | 1740 | 656±135.1 | 679±110.2 | 643±144.9 | 0.12 |
Maternal factors | | | | | |
Age years | 2313 | 32.6±4.1 | 30.9±3.2 | 32.0±4.8 | <0.001 |
Pre-pregnancy BMI | 2252 | 23.1±3.6 | 22.8±3.5 | 23.9±4.7 | 0.05 |
BMI at 18 weeks | 2278 | 24.8±3.6 | 24.8±3.6 | 25.8±4.8 | 0.016 |
Weight pre-pregnancy kg | 2263 | 65.4±11.1 | 64.8±11.1 | 66.4±13.4 | 0.55 |
Weight at inclusion kg | 2288 | 70.1±11.1 | 70.4±11.4 | 71.6±13.5 | 0.37 |
Gestational weight gain up to 18 weeks kg | 2259 | 4.7±3.2 | 5.4±3.5 | 5.3±3.8 | 0.002 |
Pregnancy history | | | | | |
Current in vitro fertilisation | 2300 | 173 (8.4) | 4 (2.7) | 0 (0.0) | <0.001 |
Miscarriage(s) <12 weeks | 2300 | | | | 0.08 |
0 | | 1531 (74.3) | 126 (84.0) | 73 (70.9) | |
1 | | 371 (18.0) | 15 (10.0) | 20 (19.4) | |
>1 | | 146 (7.1) | 9 (6.0) | 10 (9.7) | |
Miscarriage(s)/stillbirths 12–23 weeks | 2300 | | | | 0.006 |
0 | | 2006 (97.9) | 148 (98.7) | 96 (94.1) | |
1 | | 41 (2.0) | 2 (1.3) | 5 (4.9) | |
>1 | | 1 (0.0) | 0 (0.0) | 1 (1.0) | |
Parity | 2150 | | | | 0.008 |
0 | | 1124 (59.2) | 107 (71.8) | 59 (57.8) | |
1 | | 612 (32.2) | 36 (24.2) | 29 (28.4) | |
>1 | | 163 (8.6) | 6 (4.0) | 14 (13.7) | |
Sociodemographic factors | | | | | |
Education | 2141 | | | | <0.001 |
Preliminary school only | | 13 (0.7) | 1 (0.7) | 2 (2.0) | |
High school only | | 175 (9.3) | 19 (12.8) | 25 (24.5) | |
Higher education <4 years | | 580 (30.7) | 60 (40.5) | 42 (41.2) | |
Higher education ≥4 years | | 1122 (59.3) | 67 (45.3) | 33 (32.4) | |
Other | | 1 (0.1) | 1 (0.7) | 0 (0.0) | |
Country of origin | 2150 | | | | 0.005 |
Norway and Sweden | | 1683 (88.6) | 144 (96.6) | 87 (85.3) | |
Rest of the world | | 216 (11.4) | 5 (3.4) | 15 (14.7) | |
Marital status | 2150 | | | | <0.001 |
Married | | 816 (43.0) | 39 (26.2) | 30 (29.4) | |
Cohabitants | | 1037 (54.6) | 107 (71.8) | 66 (64.7) | |
Single | | 30 (1.6) | 2 (1.3) | 5 (4.9) | |
Divorced/separated | | 1 (0.1) | 0 (0.0) | 0 (0.0) | |
Other | | 15 (0.8) | 1 (0.7) | 1 (1.0) | |
Living area | 2150 | | | | 0.026 |
City, densely populated | | 716 (37.7) | 76 (51.0) | 42 (41.2) | |
City, less densely populated | | 732 (38.5) | 52 (34.9) | 33 (32.4) | |
Suburb | | 311 (16.4) | 15 (10.1) | 17 (16.7) | |
Countryside, village | | 100 (5.3) | 5 (3.4) | 5 (4.9) | |
Countryside, outside village | | 40 (2.1) | 1 (0.7) | 5 (4.9) | |
Household income | 2150 | | | | <0.001 |
Low | | 18 (0.9) | 3 (2.0) | 4 (3.9) | |
Middle | | 991 (52.2) | 87 (58.4) | 72 (70.6) | |
High | | 857 (45.1) | 57 (38.3) | 24 (23.5) | |
Not reported | | 33 (1.7) | 2 (1.3) | 2 (2.0) | |
Smoking history | | | | | |
Previous smoking | 2150 | 300 (14.6) | 75 (50.0) | 100 (98.0) | <0.001 |
In utero exposure to cigarette smoke | 2150 | | | | <0.001 |
No | | 1463 (77.0) | 87 (58.4) | 73 (71.6) | |
Yes | | 256 (13.5) | 29 (19.5) | 21 (20.6) | |
Do not know | | 180 (9.5) | 33 (22.1) | 8 (7.8) | |